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Simple Zener Diode Tester
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This is an easy to do one evening project.
It's a Zener Diode Tester you can build with just a few parts.
Often you can find a great bargin at a surplus store or at a flea market
on un-marked zener diodes. This device here will not only test for
good diodes but will tell you the zener voltage of that diode.
Zener diodes are used as voltage regulators and will begin to conduct in the
reverse or "breakdown" mode when enough voltage is applied. This voltage will
remain constant or "regulated".
To use this tester, supply enough voltage from a battery or power supply that will
cause the highest voltage zener you might have to operate. If you might have some
24 or 48 volt types then you need that voltage as a minimum.
I use 12 volts on mine
since most of the diodes I use operate below that voltage. Next turn the pot all the
way down (zero volts).
Attatch the diode and begin to increase the voltage. Watch the meter
and when it stops going any higher you have reached the "zener point" for that diode.
Now, just read the voltage on the meter and mark the diode. If the meter does not
read as you increase voltage, try reversing the diode.
If that dosent work you have
a shorted diode or it's not a zener diode.